THE CLINICAL VALIDITY OF NORMAL COMPRESSION ULTRASONOGRAPHY IN OUTPATIENTS SUSPECTED OF RAVING DEEP VENOUS THROMBOSIS

Background: Ultrasonography using Vein compression accurately detects proximal deep Venous thrombosis in symptomatic outpatients. Repeated t esting is required for patients with normal results at presentation, b ut the optimal management of such patients is uncertain. Objective: To test the safety of withholding anticoagulation in outpatients suspect ed of having first-episode deep venous thrombosis who have normal resu lts on simplified compression ultrasonography at presentation and on a single repeated test done 5 to 7 days later. Design: Prospective coho rt study. Setting: Noninvasive vascular laboratories at a university t eaching hospital and a Veterans Administration medical center. Patient s: 405 consecutive outpatients suspected of having first-episode deep Venous thrombosis. Intervention: Ultrasonography was performed at pres entation. The common femoral and popliteal veins were assessed for com pressibility. If the result was normal, anticoagulation was withheld a nd testing was repeated 5 to 7 days later. Anticoagulation was withhel d from all patients whose results remained normal according to compres sion ultrasonography, regard less of their symptoms. The safety of thi s approach was tested by follow-up lasting 3 months. Measurements: Obj ective testing was done during follow-up in all patients with symptoms or signs of venous thromboembolism. The outcome measure was symptomat ic Venous thrombosis or pulmonary embolism during follow-up, confirmed by objective testing. Results: Ultrasonography had normal results in 335 patients (83%) and abnormal results in 70 (17%). None of the patie nts with normal results died of pulmonary embolism. Venous thromboembo lism occurred during follow-up in 2 patients with normal ultrasonograp hic results (0.6% [95% CI, 0.07% to 2.14%]) and in 4 patients with abn ormal results (5.7% [CI, 1.58% to 13.99%]) (P = 0.009). Conclusions: I t is safe to withhold anticoagulation in outpatients suspected of havi ng first-episode deep venous thrombosis if results of simplified compr ession ultrasonography are normal at presentation and on a single repe ated test done 5 to 7 days later.